1. Field of the Invention
The present invention relates to a magnetic sensor element using highly-oriented diamond film and a magnetic detector suitable for use in the fields where high environmental resistance and good high-temperature stability are required.
2. Prior Art
It is known that semiconductors or semiconducting films can be used as a magnetic detector utilizing its Hall effect, i.e., a phenomenon that an electric field is produced in the direction vertical both to the electric current and the magnetic field when the electric current flows vertically to the magnetic field through a semiconducting material (for example, A Film Handbook, ed. by the File No. 131 Committee, Japan Society for the Promotion of Science, pp. 635-641 (1983)). It is also known to use the Hall elements utilizing diamond films with high temperature stability and chemical stability as said semiconducting films which may be used under high temperature of 200.degree. C. or more (Japanese under Provisional Publication hei 4-26172). Magnetic sensors, being currently sold, utilizing Si, GaAs, InAs or InSb and the like, can not be used under such a high temperature since their semiconducting characteristics are lost. Therefore, the Hall elements utilizing diamond films are attractive due to their advantage as magnetic sensors. In addition, since diamond films have an excellent thermal conductivity and a heat dissipation property, it is possible to increase the sensitivity of diamond magnetic sensors by raising the input power.
The prior art Hall elements utilizing single crystal diamonds, however, are difficult to expand their size and to integrate since availability of large single crystal of diamond is limited. Use of single crystal diamond also raises the manufacturing cost of the Hall elements. Furthermore, the prior art Hall elements are all single elements and therefore inappropriate for simultaneous measurements of magnetic fields at different places over wide area and space.
On the other hand, the Hall elements utilizing polycrystalline diamond films can be expanded their surface area and increased the integration. Further, the manufacturing cost of the Hall elements can be reduced. However, such polycrystalline diamond films contain a high density of grain boundaries which results in a low carrier mobility (about 1 cm.sub.2 /V.sec) and a low magnetic field sensitivity and therefore inappropriate for practical use.